 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui;

 import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.widgets.Composite;

 /**
  * A workbench part is a visual component within a workbench page. There
  * are two subtypes: view and editor, as defined by <code>IViewPart</code> and
  * <code>IEditorPart</code>.
  * <p>
  * A view is typically used to navigate a hierarchy of information (like the
  * workspace), open an editor, or display properties for the active editor.
  * Modifications made in a view are saved immediately.
  * </p><p>
  * An editor is typically used to edit or browse a document or input object.
  * The input is identified using an <code>IEditorInput</code>. Modifications made
  * in an editor part follow an open-save-close lifecycle model.
  * </p><p>
  * This interface may be implemented directly. For convenience, a base
  * implementation is defined in <code>WorkbenchPart</code>.
  * </p><p>
  * The lifecycle of a workbench part is as follows:
  * <ul>
  * <li>When a part extension is created:
  * <ul>
  * <li>instantiate the part</li>
  * <li>create a part site</li>
  * <li>call <code>part.init(site)</code></li>
  * </ul>
  * <li>When a part becomes visible in the workbench:
  * <ul>
  * <li>add part to presentation by calling
  * <code>part.createControl(parent)</code> to create actual widgets</li>
  * <li>fire <code>partOpened</code> event to all listeners</li>
  * </ul>
  * </li>
  * <li>When a part is activated or gets focus:
  * <ul>
  * <li>call <code>part.setFocus()</code></li>
  * <li>fire <code>partActivated</code> event to all listeners</li>
  * </ul>
  * </li>
  * <li>When a part is closed:
  * <ul>
  * <li>if save is needed, do save; if it fails or is canceled return</li>
  * <li>if part is active, deactivate part</li>
  * <li>fire <code>partClosed</code> event to all listeners</li>
  * <li>remove part from presentation; part controls are disposed as part
  * of the SWT widget tree
  * <li>call <code>part.dispose()</code></li>
  * </ul>
  * </li>
  * </ul>
  * </p>
  * <p>
  * After <code>createPartControl</code> has been called, the implementor may
  * safely reference the controls created. When the part is closed
  * these controls will be disposed as part of an SWT composite. This
  * occurs before the <code>IWorkbenchPart.dispose</code> method is called.
  * If there is a need to free SWT resources the part should define a dispose
  * listener for its own control and free those resources from the dispose
  * listener. If the part invokes any method on the disposed SWT controls
  * after this point an <code>SWTError</code> will be thrown.
  * </p>
  * <p>
  * The last method called on <code>IWorkbenchPart</code> is <code>dispose</code>.
  * This signals the end of the part lifecycle.
  * </p>
  * <p>
  * An important point to note about this lifecycle is that following
  * a call to init, createControl may never be called. Thus in the dispose
  * method, implementors must not assume controls were created.
  * </p>
  * <p>
  * Workbench parts implement the <code>IAdaptable</code> interface; extensions
  * are managed by the platform's adapter manager.
  * </p>
  *
  * @see IViewPart
  * @see IEditorPart
  */
 public interface IWorkbenchPart extends IAdaptable {

     /**
      * The property id for <code>getTitle</code>, <code>getTitleImage</code>
      * and <code>getTitleToolTip</code>.
      */
     public static final int PROP_TITLE = IWorkbenchPartConstants.PROP_TITLE;

     /**
      * Adds a listener for changes to properties of this workbench part.
      * Has no effect if an identical listener is already registered.
      * <p>
      * The property ids are defined in {@link IWorkbenchPartConstants}.
      * </p>
      *
      * @param listener a property listener
      */
     public void addPropertyListener(IPropertyListener listener);

     /**
      * Creates the SWT controls for this workbench part.
      * <p>
      * Clients should not call this method (the workbench calls this method when
      * it needs to, which may be never).
      * </p>
      * <p>
      * For implementors this is a multi-step process:
      * <ol>
      * <li>Create one or more controls within the parent.</li>
      * <li>Set the parent layout as needed.</li>
      * <li>Register any global actions with the site's <code>IActionBars</code>.</li>
      * <li>Register any context menus with the site.</li>
      * <li>Register a selection provider with the site, to make it available to
      * the workbench's <code>ISelectionService</code> (optional). </li>
      * </ol>
      * </p>
      *
      * @param parent the parent control
      */
     public void createPartControl(Composite parent);

     /**
      * Disposes of this workbench part.
      * <p>
      * This is the last method called on the <code>IWorkbenchPart</code>. At this
      * point the part controls (if they were ever created) have been disposed as part
      * of an SWT composite. There is no guarantee that createPartControl() has been
      * called, so the part controls may never have been created.
      * </p>
      * <p>
      * Within this method a part may release any resources, fonts, images, etc.&nbsp;
      * held by this part. It is also very important to deregister all listeners
      * from the workbench.
      * </p>
      * <p>
      * Clients should not call this method (the workbench calls this method at
      * appropriate times).
      * </p>
      */
     public void dispose();

     /**
      * Returns the site for this workbench part. The site can be
      * <code>null</code> while the workbench part is being initialized. After
      * the initialization is complete, this value must be non-<code>null</code>
      * for the remainder of the part's life cycle.
      *
      * @return The part site; this value may be <code>null</code> if the part
      * has not yet been initialized
      */
     public IWorkbenchPartSite getSite();

     /**
      * Returns the title of this workbench part. If this value changes
      * the part must fire a property listener event with
      * <code>PROP_TITLE</code>.
      * <p>
      * The title is used to populate the title bar of this part's visual
      * container.
      * </p>
      *
      * @return the workbench part title (not <code>null</code>)
      */
     public String getTitle();

     /**
      * Returns the title image of this workbench part. If this value changes
      * the part must fire a property listener event with
      * <code>PROP_TITLE</code>.
      * <p>
      * The title image is usually used to populate the title bar of this part's
      * visual container. Since this image is managed by the part itself, callers
      * must <b>not</b> dispose the returned image.
      * </p>
      *
      * @return the title image
      */
     public Image getTitleImage();

     /**
      * Returns the title tool tip text of this workbench part.
      * An empty string result indicates no tool tip.
      * If this value changes the part must fire a property listener event with
      * <code>PROP_TITLE</code>.
      * <p>
      * The tool tip text is used to populate the title bar of this part's
      * visual container.
      * </p>
      *
      * @return the workbench part title tool tip (not <code>null</code>)
      */
     public String getTitleToolTip();

     /**
      * Removes the given property listener from this workbench part.
      * Has no affect if an identical listener is not registered.
      *
      * @param listener a property listener
      */
     public void removePropertyListener(IPropertyListener listener);

     /**
      * Asks this part to take focus within the workbench.
      * <p>
      * Clients should not call this method (the workbench calls this method at
      * appropriate times). To have the workbench activate a part, use
      * <code>IWorkbenchPage.activate(IWorkbenchPart) instead</code>.
      * </p>
      */
     public void setFocus();
 }

